DIFFERENTIAL IMPACTS OF POLLEN QUALITY AND MICROBIAL COMMUNITIES ON GENERALIST AND SPECIALIST BEES VISITING A SHARED FOOD RESOURCE

Abstract

There is mounting evidence for declines in both managed and wild pollinator species, necessitating support for wild bee populations in order to maintain pollination services. Solitary, ground-nesting bees comprise the vast majority of bees in the world; however, these important pollinators are relatively understudied and we know little about how they are impacted by resource availability, pollen quality, and microbial associates. My dissertation research uses plants of the genus Cucurbita as a case study to assess differential health concerns associated with generalist (Bombus impatiens and Apis mellifera) and specialist (Peponapis pruinosa) pollinators on a shared resource. I begin by examining how cucurbit plant chemistry varies across plant tissue types and varieties and how this variation impacts the foraging choices of both generalist and specialist bees in an agricultural system. Next, I assess the physiological costs associated with digesting cucurbit pollen for these generalist and specialist bees. Finally, I explore the microbial community associated with a specialist ground-nesting bee’s brood cells, evaluate how this community changes over space and time, and assess the most likely routes of microbial colonization into brood cells.